// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <utility>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/macros.h"
#include "base/run_loop.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "cc/base/math_util.h"
#include "content/browser/renderer_host/input/synthetic_gesture.h"
#include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
#include "content/browser/renderer_host/render_widget_host_impl.h"
#include "content/browser/web_contents/web_contents_impl.h"
#include "content/common/input/synthetic_gesture_params.h"
#include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/common/content_switches.h"
#include "content/public/test/browser_test_utils.h"
#include "content/public/test/content_browser_test.h"
#include "content/public/test/content_browser_test_utils.h"
#include "content/public/test/test_utils.h"
#include "content/shell/browser/shell.h"

namespace {

const char kCompositedScrollingDataURL[] = "data:text/html;charset=utf-8,"
                                           "<!DOCTYPE html>"
                                           "<meta name='viewport' content='width=device-width'/>"
                                           "<style>"
                                           "#scroller {"
                                           "  width:500px;"
                                           "  height:500px;"
                                           "  overflow:scroll;"
                                           "  transform: rotateX(-30deg);"
                                           "}"

                                           "#content {"
                                           "  background-color:red;"
                                           "  width:1000px;"
                                           "  height:1000px;"
                                           "}"
                                           "</style>"
                                           "<div id='scroller'>"
                                           "  <div id='content'>"
                                           "  </div>"
                                           "</div>"
                                           "<script>"
                                           "  document.title='ready';"
                                           "</script>";

} // namespace

namespace content {

class CompositedScrollingBrowserTest : public ContentBrowserTest {
public:
    CompositedScrollingBrowserTest() { }
    ~CompositedScrollingBrowserTest() override { }

    void SetUpCommandLine(base::CommandLine* cmd) override
    {
        cmd->AppendSwitch(switches::kEnablePreferCompositingToLCDText);
    }

    RenderWidgetHostImpl* GetWidgetHost()
    {
        return RenderWidgetHostImpl::From(
            shell()->web_contents()->GetRenderViewHost()->GetWidget());
    }

    void OnSyntheticGestureCompleted(SyntheticGesture::Result result)
    {
        EXPECT_EQ(SyntheticGesture::GESTURE_FINISHED, result);
        runner_->Quit();
    }

protected:
    void LoadURL()
    {
        const GURL data_url(kCompositedScrollingDataURL);
        NavigateToURL(shell(), data_url);

        RenderWidgetHostImpl* host = GetWidgetHost();
        scoped_refptr<FrameWatcher> frame_watcher(new FrameWatcher());
        frame_watcher->AttachTo(shell()->web_contents());
        host->GetView()->SetSize(gfx::Size(400, 400));

        base::string16 ready_title(base::ASCIIToUTF16("ready"));
        TitleWatcher watcher(shell()->web_contents(), ready_title);
        ignore_result(watcher.WaitAndGetTitle());

        // We need to wait until at least one frame has been composited
        // otherwise the injection of the synthetic gestures may get
        // dropped because of MainThread/Impl thread sync of touch event
        // regions.
        frame_watcher->WaitFrames(1);
    }

    // ContentBrowserTest:
    int ExecuteScriptAndExtractInt(const std::string& script)
    {
        int value = 0;
        EXPECT_TRUE(content::ExecuteScriptAndExtractInt(
            shell(), "domAutomationController.send(" + script + ")", &value));
        return value;
    }

    int GetScrollTop()
    {
        return ExecuteScriptAndExtractInt(
            "document.getElementById(\"scroller\").scrollTop");
    }

    // Generate touch events for a synthetic scroll from |point| for |distance|.
    // Returns the distance scrolled.
    int DoTouchScroll(const gfx::Point& point, const gfx::Vector2d& distance)
    {
        EXPECT_EQ(0, GetScrollTop());

        int scrollHeight = ExecuteScriptAndExtractInt(
            "document.getElementById('scroller').scrollHeight");
        EXPECT_EQ(1000, scrollHeight);

        SyntheticSmoothScrollGestureParams params;
        params.gesture_source_type = SyntheticGestureParams::TOUCH_INPUT;
        params.anchor = gfx::PointF(point);
        params.distances.push_back(-distance);

        runner_ = new MessageLoopRunner();

        std::unique_ptr<SyntheticSmoothScrollGesture> gesture(
            new SyntheticSmoothScrollGesture(params));
        GetWidgetHost()->QueueSyntheticGesture(
            std::move(gesture),
            base::Bind(&CompositedScrollingBrowserTest::OnSyntheticGestureCompleted,
                base::Unretained(this)));

        // Runs until we get the OnSyntheticGestureCompleted callback
        runner_->Run();
        runner_ = NULL;

        return GetScrollTop();
    }

private:
    scoped_refptr<MessageLoopRunner> runner_;

    DISALLOW_COPY_AND_ASSIGN(CompositedScrollingBrowserTest);
};

// Verify transforming a scroller doesn't prevent it from scrolling. See
// crbug.com/543655 for a case where this was broken.
// Disabled on MacOS because it doesn't support touch input.
// Disabled on Android due to flakiness, see https://crbug.com/376668.
#if defined(OS_MACOSX) || defined(OS_ANDROID)
#define MAYBE_Scroll3DTransformedScroller DISABLED_Scroll3DTransformedScroller
#else
#define MAYBE_Scroll3DTransformedScroller Scroll3DTransformedScroller
#endif
IN_PROC_BROWSER_TEST_F(CompositedScrollingBrowserTest,
    MAYBE_Scroll3DTransformedScroller)
{
    LoadURL();
    int scrollDistance = DoTouchScroll(gfx::Point(50, 150), gfx::Vector2d(0, 100));
    // The scroll distance is increased due to the rotation of the scroller.
    EXPECT_EQ(std::floor(100 / std::cos(cc::MathUtil::Deg2Rad(30.f))) - 1,
        scrollDistance);
}

} // namespace content
